Fabrication and luminescence behavior of phosphate glass ceramics co-doped with Er3+ and Yb3+

Transparent phosphate glass ceramics co-doped with Er³⁺ and Yb³⁺ in the system P₂O₅Li₂OCaF₂TiO₂ were successfully synthesized by melt-quenching and subsequent heating. Formation of the nanocrystals was confirmed by X-ray powder diffraction. Judd–Ofelt analyses of Er³⁺ ions in the precursor glasses and glass ceramics were performed to evaluate the intensity parameters Ω_2,4,6. Under 975 nm excitation, intense upconversion (UC) and infrared emission (1545 nm) were observed in the glass ceramics by efficient energy transfer from Yb³⁺ to Er³⁺. The luminescence processes were explained and the emission cross section was calculated by Fuchtbauer–Ladenburg (F–L) formula. The results confirm the potential applications of Er³⁺/Yb³⁺ co-doped glass ceramics as laser and fiber amplifier media.     

Lead−barium fluoroborate glass ceramics doped with Nd<Superscript>3+</Superscript> or Er<Superscript>3+</Superscript>

Lead?barium fluoroborate glasses in the PbF₂–BaF₂–B₂O₃, PbF₂–BaO–B₂O₃, and PbO_– BaF₂–B₂O₃ systems doped with rare-earth ions (Nd³⁺ or Er³⁺) are synthesized and studied. It is shown that, based on these glasses, it is possible to produce transparent glass ceramics with fluoride crystalline phases, including ceramics with one crystalline phase of the fluorite structure. The spectral and luminescent properties of the doped glasses, glass ceramics, and polycrystalline complex fluorides containing Pb, Ba, and rare ions are studied.     

Barium borate glass and transparent glass ceramics doped with Pb4Lu2YbF17

Barium borate glasses doped with complex Pb₄Lu₂YbF₁₇ fluoride have been synthesized and investigated. Heat treatment produced glass ceramics containing the crystalline BaF₂:Yb³⁺ phase. The changes in the structural and optical properties of the glass ceramics were revealed by X-ray diffraction, Raman spectroscopy, and luminescence spectroscopy of Yb³⁺ ions in polycrystalline Pb₄Lu₂YbF₁₇, initial glass, and glass ceramics.     

Luminescence of transparent glass ceramics containing Er<Superscript>3+</Superscript> and Yb<Superscript>3+</Superscript> zirconate-titanate nanocrystals

Luminescence regularities have been studied in new erbium/ytterbium materials based on glasses and glass ceramics of a magnesium-aluminosilicate system containing nanoscale erbium/ytterbium zirconate titanate crystals with the pyrochlore structure. Lifetimes of Yb³⁺ and Er³⁺ ions in the ² F_5/2 state and in the ⁴I_11/2 and ⁴I_13/2 states, respectively, and the efficiency of Yb³⁺ → Er³⁺ energy transfer have been evaluated. The identified spectral-luminescent characteristics of the studied glasses and glass ceramics co-doped with erbium and ytterbium ions show that these materials are promising media for producing laser generation in the spectral range around 1.5 μm.     

Measurement of optical dephasing of Eu3+ and Pr3+ doped silicate glasses by spectral holeburning

Long-lived spectral holeburning has been observed in Eu³⁺ and Pr³⁺ doped silicate glasses, and used to measure homogeneous linewidths (φ_h). In the case of Eu³⁺, holes are burned by optical pumping of nuclear quadrupole levels, and our low temperature measurement of φ_h shows that the previously determined T^1.8 temperature dependence holds down to at least 1.6 K. On the other hand, in Pr³⁺ doped glass, holes are burned by optically induced local lattice rearrangements. In contrast to previously studied inorganic glasses, we find a linear temperature dependence of φ_h for the ³H₄ ? ¹D₂ transition from 1.6 K to 20 K. This was confirmed by picosecond accumulated grating photon echoes. Current theories of dephasing in glasses do not predict these temperature dependences. Holeburning has also been observed in Pr³⁺ doped BeF₂ and phosphate glasses and Nd³⁺ doped silicate glass and thus appears to be a rather general phenomenon in inorganic glasses, as has been found for molecules in organic glasses.     

Enhancement of up-conversion luminescence in Zn2SiO4:Yb3+, Er3+ by co-doping with Li+ or Bi3+

Yb³⁺/Er³⁺ co-doped Zn₂SiO₄ ceramics are rapidly synthesized by the microwave radiation method. Green and red up-conversion emissions are observed in Zn₂SiO₄: Yb³⁺, Er³⁺ ceramics under 980 nm excitation. The influence of co-doped Li⁺ or Bi³⁺ ion on luminescence intensity for the phosphors has been investigated. At Li⁺ or Bi³⁺ doping concentration of 1 mol%, up-converted green emission can be increased by 6 times and 20 times, respectively. It is believed that co-doped Li⁺ or Bi³⁺ ion results in the local distortion of Er³⁺ in Zn₂SiO₄, increasing the intra-4f transitions of Er³⁺ ions. The local distortion is proved by spectral probing method with Eu³⁺.     

Blue light emission from Eu ions in sol-gel-derived Al2O3-SiO2 glasses

Blue light-emitting glasses were successfully prepared by doping Eu²⁺ ions in the system Al₂O₃-SiO₂. The Al₂O₃-SiO₂ glasses doped with Eu³⁺ ions were synthesized using a sol-gel method, followed by heating in hydrogen gas atmosphere to reduce into the Eu²⁺ ions. The obtained glasses exhibited emission spectra with peak at ∼450 nm due to 4f⁶5d→4f⁷ (⁸S_7/2) transition, the intensities of which strongly changed depending on their glass composition and heating conditions. The emission quantum efficiency of 48% was achieved by heating the glass with the ratio of Al³⁺ to Eu³⁺ at about 6 at 1000 °C in hydrogen gas atmosphere. It was found that the Al₂O₃-SiO₂ glasses were appropriate not only for homogeneously doping the Eu³⁺ ions in glass structure but also reducing to Eu²⁺ ions, resulting in enhanced blue light-emission properties.     

X-ray photoelectron spectroscopy of Sm-doped CaO-MgO-Al2O3-SiO2 glasses and glass ceramics

Sm³⁺ doped CaO-MgO-Al₂O₃-SiO₂ glass and glass ceramics have been prepared. The diopside crystal (CaMgSi₂O₆) was identified in the glass ceramics by X-ray diffraction analysis. X-ray photoelectron spectra of the glass and glass ceramics were measured by a monochromatised Al-Kα XPS instrument. Sm 3d core level spectra for the Sm doped samples showed that Sm ions are predominantly in the Sm (III) state in glass and glass ceramics. The O 1s core spectra could be fitted by summing the contributions from bridging oxygen (BO) and non bridging oxygen (NBO) for samarium undoped glass, BO, NBO and Si-O-Sm for the doped glass. The O 1s XPS spectrum of undoped glass ceramics was curve fitted with BO and NBO in glass phase, as well as SiOSi, SiOMg and SiOCa in diopside. In addition to the five components above mentioned, SiOSm in diopside also appeared in O 1s XPS spectra of samarium doped glass ceramics. According to the fitting results, we demonstrate that the Sm₂O₃ exist in glass network as a glass modifier. After heat treatment, nearly all the Sm³⁺ existed in diopside phase as the substitution for Ca²⁺.     

Mössbauer study of various fluoride glasses containing iron fluoride

(PbF₂, ZnF₂, AlF₃, or ZrF₄) - (BaF₂ and CaF₂) - FeF₃ glasses with 20 or 30 mol%FeF₃ contents were studied by ⁵⁷Fe Mössbauer spectroscopy. The Mössbauer spectrum at room temperature for the PbF₂-based glass is composed of one doublet due to Fe³⁺, whereas those for the ZnF₂?, AlF₃?, and ZrF₄-based glasses, two doublets due to Fe³⁺ and Fe²⁺. Both the iron ions have octahedral F coordination in the high spin states. The Fe²⁺/(Fe²⁺ + Fe³⁺) value in glass increases with the basicity of base glass.     

掺铒铋酸盐玻璃的光谱性质研究

研究了掺铒铋酸盐玻璃的吸收和荧光光谱性质,应用Judd-Ofelt理论计算了玻璃的三个强度参量Ω_t=(t=2,4,6),分别为Ω₂=3.71×10^-20cm²,Ω₄=1.86×10^-20cm²,Ω₆=1.28×10^-20cm²,计算了Er³⁺离子的自发跃迁几率、荧光分支比等光谱参量.经荧光谱测试发现掺Er³⁺铋酸盐玻璃的荧光半高宽可达70nm.应用McCumber理论计算1.53μm处的受激发射截面可达9×10^-21cm².对Er³⁺离子在不同基质玻璃中光谱特性的比较发现,Er³⁺在铋酸盐玻璃中具有相对较高的受激发射截面和宽的荧光半高宽.     

Photoacoustic Spectra of Sm3+, Eu3+, Dy3+ Complexes

The complexes crystals of Sm(Ac)3.4H₂O, Eu(Ac)3.4H₂O and a new complex Dy2(Ac)(NO3)4.12H₂O were synthesized and their PA spectra were determined firstly. All their PA spectra absorptions are interpreted. The fluorescence properties of Sm³⁺, Eu³⁺, Dy³⁺ and the relaxation process models were studied by their PA spectra.     

Luminescence centers in silicate and germanate glasses activated by bismuth

Concentration series of silicate and germanate glasses activated by bismuth are studied. It is shown that luminescence in the IR region is controlled by several active centers related to bismuth. Based on a comparison of spectroscopic characteristics of the studied glasses with the data previously obtained for chloride glass, the observed centers were identified as Bi⁺, Bi ₂ ⁴⁺ , and Bi ₅ ³⁺ in germanate glass and Bi⁺, Bi ₂ ⁴⁺ in silicate glass.     

Energy transfer from the host to Er<Superscript>3+</Superscript> dopants in semiconductor SnO<Subscript>2</Subscript> nanocrystals segregated in sol–gel silica glasses

Undoped and Er³⁺-doped glass–ceramics of composition (100−x)SiO₂–xSnO₂, with x = 5 or 10 and with 0.4 or 0.8 mol% of Er³⁺ ions, were synthesised by thermal treatment of precursor sol–gel glasses. Structural studies were developed by X-Ray Diffraction. Wide band gap SnO₂ semiconductor quantum-dots embedded in the insulator SiO₂ glass are obtained. The mean radius of the SnO₂ nanocrystals, ranging from 2 to 3.2 nm, is comparable to the exciton Bohr radius. The luminescence properties have been analysed as a function of sample composition and thermal treatment. The results show that Er³⁺ ions are partially partitioned into the nanocrystalline phase. An efficient UV excitation of the Er³⁺ ions by energy transfer from the SnO₂ nanocrystal host is observed. The Er³⁺ ions located in the SnO₂ nanocrystals are selectively excited by this energy transfer mechanism. On the other hand, emission from the Er³⁺ ions remaining in the silica glassy phase is obtained by direct excitation of these ions.     

Er3+及Er3+/Yb3+共掺铋酸盐玻璃光谱性质研究

制备了Er³⁺及Er³⁺/Yb³⁺共掺铋酸盐玻璃，测试了样品的吸收光谱、荧光光谱.应用Judd-Oflet理论计算了Er³⁺在铋酸盐玻璃中的光谱强度参数，分别为Ω₂=(5.47—2.92)×10^-20cm²，Ω₄=(2.16—1.22)×10^-20cm², 关键词： 3+')" href="#">Er³⁺ 铋酸盐玻璃 3+/Yb³⁺共掺')" href="#">Er³⁺/Yb³⁺共掺 光谱性质     

Emission features of Ho ion in Nb2O5, Ta2O5 and La2O3 mixed Li2O-ZrO2-SiO2 glasses

Li₂O-ZrO₂-SiO₂: Ho³⁺ glasses mixed with three interesting d-block elemental oxides, viz., Nb₂O₅, Ta₂O₅ and La₂O₃, were prepared. Optical absorption and photoluminescence spectra of these glasses have been recorded at room temperature. The luminescence spectra of Nb₂O₅ and Ta₂O₅ mixed Li₂O-ZrO₂-SiO₂ glasses (free of Ho³⁺ ions) have also exhibited broad emission band in the blue region. This band is attributed to radiative recombination of self-trapped excitons (STEs) localized on substitutionally positioned octahedral Ta⁵⁺ and Nb⁵⁺ ions in the glass network. The Judd-Ofelt theory was successfully applied to characterize Ho³⁺ spectra of all the three glasses. From this theory various radiative properties, like transition probability A, branching ratio β_r and the radiative lifetime τ_r, for ⁵S₂ emission levels in the spectra of these glasses have been evaluated. The radiative lifetime for ⁵S₂ level of Ho³⁺ ions has also been measured and quantum efficiencies were estimated. Among the three glasses studied the La₂O₃ mixed glass exhibited the highest quantum efficiency. The reasons for such higher value have been discussed based on the relationship between the structural modifications taking place around the Ho³⁺ ions.     

Tm3+/Yb3+共掺铋碲酸盐玻璃中的高效蓝色上转换荧光

制备了高折射率Tm³⁺/Yb³⁺共掺杂铋碲酸盐玻璃，利用棱镜耦合法测量出玻璃在632.8和1550nm波长处的折射率分别为2.0365和1.9795. 对玻璃的吸收、荧光和红外透过光谱展开了测试与分析，根据Judd-Ofelt理论对吸收光谱进行拟合，求得Tm³⁺的振子强度参数Ω_t(t=2，4，6)分别为3.90×10^-20, 2.03×10^-20和9.03×10^{-2 关键词： 3+}/Yb³⁺共掺')" href="#">Tm³⁺/Yb³⁺共掺 铋碲酸盐玻璃 光谱参数 上转换荧光     

Fabrication, photoluminescence, and potential application in white light emitting diode of Dy3+–Tm3+ doped transparent glass ceramics containing GdSr2F7 nanocrystals

Dy³⁺–Tm³⁺ doped transparent glass ceramics containing GdSr₂F₇ nanocrystals were fabricated successfully by a melt-quenching method and subsequent heating. X-ray diffraction and transmission electron microscopy analyses show that tetragonal GdSr₂F₇ nanocrystals are homogeneously precipitated among the borosilicate glass matrix. If excited with 354 nm UV light, the photoluminescence spectrum of Dy³⁺ single-doped transparent glass ceramics shows white-light emission. With doping of Tm³⁺, the overall emission color of Tm³⁺–Dy³⁺ co-doped transparent glass ceramics can be tuned from white to blue through energy transfer between Dy³⁺ and Tm³⁺. CIE chromaticity and color temperature measurements show that the resulting TGCS may be a candidate as a white LED material pumped by a UV InGaN chip.     

Synthesis and electrochemical properties of Li2S–B2S3–Li4SiO4

New Li⁺ ion-conductive glasses Li₂S–B₂S₃–Li₄SiO₄ were synthesized by rapid quenching, and they were transformed into glass ceramics by heat treatment. The heat treatment increased the ionic conductivities of the Li₄SiO₄-doped glasses, and the highest ionic conductivity observed in the system was 1.0 × 10^− 3 S cm^− 1 at room temperature. The glass ceramics were highly stable against electrochemical oxidation with a wide electrochemical window of 10 V.     

Er3+/Yb3+掺杂氟硅铅酸盐微晶玻璃的上转换发光

制备了微晶体尺寸大约在10—12 nm范围内的Er³⁺,Yb³⁺共掺杂透明氟硅铅酸盐微晶玻璃.相同功率激发下,纳米微晶玻璃中Er³⁺离子的²H_11/2,⁴S_3/2→⁴I_15/2的绿色上转换荧光和⁴F_9/2→关键词： 3+')" href="#">Er³⁺ 3+')" href="#">Yb³⁺ 能量传递 纳米微晶玻璃     

Er3+/Yb3+共掺的氧化镧钇透明陶瓷的光谱性能研究

采用传统无压烧结工艺制备了Yb³⁺/Er³⁺共掺的氧化镧钇透明陶瓷并对其光谱性能进行了研究.样品具有较大的吸收和发射截面.La₂O₃的添加使样品的荧光寿命(τ_s)与玻璃接近，当Yb³⁺和Er³⁺的掺杂量分别为5at%和0.5at%时，测得τ_s=9.65　ms.这种荧光寿命长、发射截面大和线宽窄的特性有利于微型、可集成化和大功率激光输出的实现. 关键词： 透明陶瓷 吸收光谱 发射光谱 荧光寿命